Septic water treatment method for removing carbonaceous and nitrogenous compounds

ABSTRACT

Water treatment structures may have at least a first geotextile fabric layer; a second geotextile fabric layer; a third geotextile fabric layer; a first filler layer with plastic particles, arranged between the first and second geotextile fabric layers; and a second filler layer with plastic particles, arranged between the second and third geotextile fabric layers, wherein the geotextile fabric layers and the filler layers are within a housing, and wherein the structure is configured such that contaminated water proceeds sequentially through the first geotextile fabric layer, the first filler layer, the second geotextile fabric layer, the second filler layer, and the third geotextile fabric layer. Methods of treating wastewater may involve passing wastewater, after optional oxygenating and pre-filtering, through such alternating layers of geotextile, preferably nonwoven, and polymer particles.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to water purification systems,particularly those for the treatment of domestic wastewater, such ashousehold and/or business sewer and wastewater, particularly

Description of the Related Art

Millions of homes in the world and about 25% in the US are not connectedto a local (centralized) sewer system. Homes without sewer connectionshave to either store their wastewater in septic tanks or treat theirwastewater on-site, discharging either to groundwater or to a nearbysurface water. There are several known treatment systems available foron-site wastewater treatment. The oldest known treatment technique is afilter that contains a filter bed of layered sand and gravel. However,there are several limitations with sand filters, including inefficienttreatment and clogging of the filter bed. To eliminate theselimitations, synthetic filters have been developed in last decades.Synthetic filters are compact, lightweight, and effective.

An idealized two-dimensional projection of a continuous biofilm thatadheres to geotextile fibers, e.g., a boundary biofilm similar to theslime layer that coats the surfaces of granular filters, is seen in FIG.1A. In the model in FIG. 1A, increasing the biomass thickens the filmwhich thus encroaches on the liquid transport channels. Increasing thebiomass also reduces the contact area between permeating influent andthe biofilm, reducing mass transfer, and presumably, reducing thetreatment efficiency. This effect could lead to clogging fromaccumulation of inactive residual organic waste.

Polyester (PET) or polypropylene (PP) geotextile fibers are hydrophobic,with complex pore structures. Suspended solid particles carryingattached microorganisms may become entrapped while percolating through amatrix with varying pore sizes, by sufficient immobilized particles at arestrictive channel arresting particle convection. Such convectionarrest can result in minimal contact with the fiber “cage” except at thedownstream end. Total suspended solids (TSS) can include attachedmicroorganisms, which can use the solid and passing solutes assubstrates to construct an individual floc (i.e., flocculation orflocculent at least semi-solid, rather than a continuous biofilm).Biomass having floc morphology generally “rattles” in a pore, until itagglomerates with or connects to another floc in an adjacent pore. Theresult of such agglomeration may be that water conveying fresh,dissolved, or colloidal substrate, circulates in laminar flow around thebiomass, which may have a higher specific surface for substrate transferthan the boundary biofilm of FIG. 1B. Moreover, neither the drag surfacearea nor pore blockage would increase as fast as biomass growth, therebylimiting the permeability loss. Thus, the morphology of the biomass isinfluential in assessing the threshold at which increased organicretention becomes deleterious. Such morphology is still more complex ingeotextiles with a third dimension, i.e., interior porosity.

Conventional sand filters may not be able to reduce carbonaceous andnitrogenous compounds from the residential wastewaters to sufficientlevels. The unremoved compounds can contaminate the water body, e.g.,groundwater or surface water, to which the treated effluent isdischarged. Nitrogenous compounds are especially difficult to remove inconventional sand filters that treat septic effluents. Anotherdisadvantage of conventional sand filters is that they often clog due tothe accumulation of solid materials or biofilm, causing flooding, e.g.,in the yards or gardens of single homes, which increases the possibilityof mosquito breeding and other disease casing agents.

Recent developments in geotextile filters for treating landfill leachateaddress at least some of the known clogging problems. Certainwell-designed layered geotextile systems may be superior to conventionalonsite systems in reducing the two basic secondary treatment indicators,total suspended solids (TSS) and 5-day biochemical oxygen demand (BOD₅),in nitrifying, and partially denitrifying the effluent. Certain researchin the art in this regard warrants discussion.

CN 206599509 U by Zhang et al. (Zhang) discloses a planting island forsewage treatment, with a tube-shaped casing, a waffle slab seal underthe casing, ceramic particle packing filler on the waffle slab in thecasing, a polystyrene foam layer filler on the ceramic particle packinglayer, a polystyrene foam layer top including a geotextile layer, aplastic fiber packing layer on the geotextile layer top, and a plasticnet mesh upon the plastic fiber packing layer. Zhang's geotextile canfilter, degrade pollutants, and restrain water insoluble pollutants.Zhang's system requires a ceramic particle filler and polymer foams, andZhang fails to describe multiple geotextile layers, nor polymerparticulate fillers, nor nonwovens.

CN 108867612 A by Wang et al. (Wang) discloses a grating reinforcedgeotechnical filler structure comprising a multi-layered biaxial geogridand a U-shaped nail fixing the biaxial geogrid, wherein the biaxialgeogrid is filled with a geotechnical filler formed through mixing ofsteel slag and rubber particles. Wang's geotechnical filler structure isprepared from grating reinforced steel slag and the rubber particles viaa paving method, using waste steel slag and abandoned tire industrialwaste. Wang's system is non-deformable and does not use nonwovengeotextiles or non-elastomeric plastic particles. Moreover, Wang relatesto geotechnical applications, not wastewater treatment.

CN 101224923 B by Cui et al. (Cui) discloses a method for filtering andtreating domestic sewage by using a multi-level biomembrane. Cui'smethod mechanically pre-treats and pre-aerates domestic sewage, feedsthe domestic sewage into a first level biological prefiltration reactionvessel, feeds the prefiltered sewage into a second level up-flow typedouble layer biomembrane filtration bed under aeration andoxygenization, and feeds the double-layer filtered sewage into a thirdbiomembrane filtration section. Cui uses three reactors in-series: afirst reactor filled with 3 to 5 mm plastic particles for prefiltration;a second reactor with a biomembrane filter and an up-flow floatingplastic filter; and a third reactor which is a biomembrane reactor.Cui's biofilm carrier can be ceramsite, quartz sand, volcanic rock,zeolite, or activated carbon, but Cui does not mention geotextiles ornonwovens.

JP H08-294699 A by Katsuyuki (Katsuyuki) discloses a biologicaldenitrification apparatus with fixed beds packed with floatablepolyethylene or polypropylene granular filter material with specificgravity of 0.85 to below 1 and preferably a particle size of about 2 to4 mm, and an inflow part allowing water to be treated to flow in thelower part of a first fixed bed including an intermediate aerator.Katsuyuki does not disclose multiple layers of a geotextile, nor anonwoven, and Katsuyuki's process is anaerobic.

U.S. Pat. No. 6,383,373 to Nakao et al. (Nakao) discloses a biologicalfiltration apparatus with a raw water introducing section, abiofiltration section for biologically purifying-refining-filtering theraw water yielding processed water, a liquid and gas permeable supportsection for supporting the biofiltration section, and a water collectingsection for the processed water. Nakao's biofiltration section includesa packed bed of hollow carrier resin particles with a specific gravityof 1.01 to 1.2 g/mL. While Nakao may use resin (plastic material) alone,Nakao preferably uses a mixture of a resin and an additive for adjustingspecific gravity, such as pulp, waste plastics, zeolite, barium sulfate,and slaked lime. Nakao does not disclose multiple layers of ageotextile, nor a nonwoven.

The doctoral thesis of Eyüp Korkut at Drexel University, entitled“Geotextiles as Biofilm Attachment Baffles for Wastewater Treatment,”submitted June 2003, in the Department of Civil, Architectural, andEnvironmental Engineering (Korkut) discloses a bench scale pilot plantstudy using geotextile baffles as biofilm attachment media forwastewater treatment. Korkut's system removed suspended solids andhosted growth of microorganisms to absorb and decompose carbonaceous andnitrogenous pollutants from Philadelphia Water Department (PWD)wastewater having combined sanitary and storm sewage. Korkut'sonce-through hydraulic loading rate was 20 gal/day-sq·ft. Korkut hangsgeotextile coupons as baffles transverse to the flow in a sinusoidalpattern to increase path length and contact area, using elements fromlamella settlers, granular depth filters, and trickling filters,describing nonwoven needle punched geotextiles to host a substantialbiomass. Korkut does not disclose plastic particles, nor multiple layersof nonwoven geotextile, but instead single-layer, vertically hunggeotextile filters in a fish tank filled with wastewater similar to abatch reactor.

The North American Geosynthetics Society (NAGS) conference paper andpresentation entitled, “Geotextile Biofilters for Wastewater Treatment,”by inventor Cevat Yaman (Yaman) from January, 2005, in Las Vegas, NV,discloses pilot plant study using geotextile filters as biofilmattachment media in wastewater treatment. Yaman's geotextiles filtersuspended solids and hosted growth of microorganisms to decomposecarbonaceous and nitrogenous compounds. Yaman's 10.16 cm (4 inch)diameter packed columns contain alternating layers of gravel, sand, andgeotextile filters. Yaman indicates that nonwoven needle punchedgeotextiles with complex structures and high internal porosity weresuitable for water purification. Yaman describes that primary treatmenteffluent at a net rate of 365 L/m²·day (9.0 gal/day/ft²) reduced TSS andBOD5 over 90%, NH₄ over 90%, and effluent nitrate below 10 mg/L. Yamandoes not does not describe plastic particles between layers ofgeotextile, and Yaman uses only one or two layers of (optionallynonwoven) geotextile.

In light of the above, a need remains for wastewater treatment systems,particularly using lighter materials, such as nonwoven geotextiles andplastic particles, especially polyolefin nonwovens and particles, ratherthan inorganic particles, and methods of making and using such watertreatment systems.

SUMMARY OF THE INVENTION

Aspects of the invention provide water treatment structures, which maycomprise: a first geotextile fabric layer; a second geotextile fabriclayer; a third geotextile fabric layer; a first filler layer comprisingplastic particles, arranged between the first and second geotextilefabric layers; and a second filler layer comprising plastic particles,arranged between the second and third geotextile fabric layers, whereinthe geotextile fabric layers and the filler layers are contained withina housing, and wherein the structure is configured such thatcontaminated water proceeds sequentially through the first geotextilefabric layer, the first filler layer, the second geotextile fabriclayer, the second filler layer, and the third geotextile fabric layer.Such water treatment structures may be modified by any permutation ofthe features described herein, particularly the following.

Inventive water treatment structures may further comprise: a fourthgeotextile fabric layer; and a third filler layer comprising plasticparticles, arranged between the third and fourth geotextile fabriclayers.

The first, second, and/or third geotextile fabric layer may comprise anonwoven. The first, second, and/or third geotextile fabric layer maycomprise a polyolefin and/or polyester nonwoven. The first, second,and/or third geotextile fabric layer may comprise at least 75 wt. %,relative to total fabric layer weight, of a nonwoven that may compriseat least 75 wt. %, relative to total nonwoven weight, of polypropyleneor polyethylene terephthalate. The first, second, and/or thirdgeotextile fabric layer, independently may have a thickness in a rangeof from 1 to 10 mm.

At least 90 wt. % of the plastic particles may be solid plastic. Theplastic particles may comprise at least 50 wt. % recycled polymer,relative to total particle weight. The plastic particles may have anaverage largest dimension in a range of from 5 to 60 mm.

The filler layers may be packed with the plastic particles, such thatthe geotextile fabric layers require no further structural supportwithin the housing.

Inventive water treatment structures may have a weight per volume,without water and without the housing, of less than 1000 kg/m³.

Aspects of the invention provide wastewater treatment systems, which maycomprise any permutation of inventive water treatment structure(s)described herein; and a first separate space, separated by a barrierfrom the fabric layers and the filler layers, configured to allow anoxygenation of the contaminated water. Such wastewater treatment systemsmay be modified by any permutation of the features described herein

Inventive systems may further comprise: a second separate space,separated by a barrier from the fabric layers and the filler layers,configured to collect effluent downstream of the water treatmentstructure. Inventive systems may further comprise a recycle configuredto feed effluent from downstream of the water treatment structure to apoint upstream of the water treatment structure. Inventive systems mayfurther comprise a septic tank and/or a solids separation device,upstream of the water treatment structure. Inventive systems may furthercomprise a device configured to remove organics lighter than waterupstream of the water treatment structure. Inventive systems system mayfurther comprise an aeration and/or oxygenation device, configured tointroduce oxygen into the contaminated water upstream of the watertreatment structure.

Aspects of the invention provide methods for reducing a content of oneor more carbonaceous and/or nitrogenous compounds from contaminatedwater containing the carbonaceous and/or nitrogenous compound(s). Suchmethods may be modified by any permutation of the features describedherein. For example, such methods may comprise: passing a contaminatedwater, comprising a carbonaceous and/or nitrogenous compound, at leastonce sequentially through a first geotextile fabric layer, a firstfiller layer comprising plastic particles, a second geotextile fabriclayer, a second filler layer comprising plastic particles, and a thirdgeotextile fabric layer, to obtain an effluent exiting a final layer,wherein the first filler layer is arranged between the first and secondgeotextile fabric layers, wherein the second filler layer is arrangedbetween the second and third geotextile fabric layers, and wherein thepassing reduces a content of the carbonaceous and/or nitrogenouscompound in the effluent, relative to the contaminated water. Thepassing may further comprise passing the contaminated water through athird filler layer, comprising plastic particles, and a fourthgeotextile fabric layer, wherein the third filler layer is arrangedbetween the third and fourth geotextile fabric layers. Inventive methodsmay further comprise recycling the effluent for a second cycle of thepassing. The contaminated water may be oxygenated to a dissolved oxygencontent at least 3 mg/L.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1A shows a two-dimensional pictorial representation of an attachedbiofilm mass within a fiber network represented linearly for simplicity;

FIG. 1B shows a two-dimensional pictorial representation floc(suspended, unattached) biomass within a fiber network representedlinearly for simplicity;

FIG. 2 shows pictorial representation of an exemplary water treatmentsystem;

FIG. 3 shows a cross-sectional pictorial representation of an exemplarynonwoven geotextile fabric operating within the scope of the invention,including attached and suspended biomass growth, including a zoomed-inportion on the bottom right;

FIG. 4 shows a cross-sectional pictorial representation of exemplaryplastic particles illustrating attached biomass growth on the surfacesof the particles in the zoomed in portion on the lower right;

FIG. 5A shows a pictorial representation of water treatment devicewithin the scope of the invention having additional layers and anaeration tank atop the device; and

FIG. 5B shows a pictorial representation of water treatment devicewithin the scope of the invention having additional layers and anoxygenation device attached to or embedded into a wastewaterfeed/effluent recycle pipe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Aspects of the invention provide water treatment structures comprising,e.g.: a 1^(st), 2^(nd), 3^(rd), 4^(th), 5^(th), 6^(th), 7^(th), 8^(th),9^(th), 10^(th) (or further) geotextile fabric layer; a 1^(st), 2^(nd),3^(rd), 4^(th), 5^(th), 6^(th), 7^(th), 8^(th), 9^(th), 10^(th) (orfurther) filler layer comprising plastic particles, arranged between the1^(st) and 2^(nd), 2^(nd) and 3^(rd), 3^(rd) and 4^(th), 4^(th) and5^(th), 5^(th) and 6^(th), 6^(th) and 7^(th), 7^(th) and 8^(th), 8^(th)and 9^(th), 9^(th) and 10^(th), . . . and/or n^(th) and (n+1)^(th),geotextile fabric layers. The geotextile fabric layers and the fillerlayers may be contained within a housing of basically unlimitedstructure, though constructional convenience may urge cylindrical orrectangular prismic structures, optionally with conical bases. Suchstructure may be configured such that contaminated water proceedssequentially through the first geotextile fabric layer, the first fillerlayer, the second geotextile fabric layer, the second filler layer, andthe third geotextile fabric layer, etc., until producing an effluentafter the final layer, e.g., at the base of the housing or of a wallwithin the housing containing the geotextile and plastic particlelayers. Generally, the structures will contain alternating layerscomprising geotextile and layers comprising plastic particles, oneimmediately contacting the other, generally bound only by the housingand any necessary piping/plumbing elements, e.g., to deliver liquids andgases to the layers, and/or with fixing elements for affixing thegeotextile layers to the internal housing walls. Housings may be made ofa variety of materials, and, depending upon the application, may be of aplastic, such as PE, PP, or PET, cement or concrete, metal, such asstainless steel, galvanized steel, or copper, or glass. The structuresmay preferably be located externally to a building, but may also beintegrated into a building, even as a structural unit, such as a pylon.

Any or all of the geotextile fabric layers may comprise a nonwoven,which may make out at least 50, 60, 70, 75, 80, 85, 90, 95, 97.5, 98,99, 99.9, or 100 vol. % of the total fabric layer volume. Relevantnonwovens may comprise at least 75, 80, 85, 90, 91, 92, 92.5, 93, 94,95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. % of a polyolefinand/or polyester, or any other polymer described below, relative to thetotal weight of the nonwoven. The geotextile fabric layers mayindependently comprise at least 75, 80, 85, 90, 91, 92, 92.5, 93, 94,95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. %, relative to totalfabric layer weight, of a nonwoven that may comprise at least 75, 80,85, 90, 91, 92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or99.9 wt. %, relative to total nonwoven weight, of polypropylene (PP) orpolyethylene terephthalate (PET). That is, the geotextile layer(s) mayconsist essentially of PP and/or PET nonwovens (i.e., containing onlyadditional components which do not reduce the temporal and/or volumetricdecomposition efficiency by any more than 5%). Any or all of thegeotextile fabric layers may have a thickness in a range of from 1 to 10mm, e.g., at least 1, 1.5, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, or 4mm and/or up to 10, 9, 8, 7.5, 7, 6.5, 6, 5.75, 5.5, 5.25, 5, 4.75, 4.5,4.25, 4, 3.75, 3.5, 3.25, or 3 mm.

At least 90, 91, 92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99, 99.1, 99.5,or 99.9 wt. % of the plastic particles may be solid plastic, relative tothe total plastic particle weight, whereby a remainder may be at leastpartially hollow, e.g., 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40,37.5, 33, 25, 20, 15, 10, 7.5, 5, 4, 3, 2, 1, or 0.5 vol. % internallyvacant, based on the average total particle volume (disregardingexternal voids). The plastic particles may comprise at least 50, 60, 70,75, 80, 85, 90, 91, 92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99, 99.1,99.5, or 99.9 wt. % recycled polymer, relative to total particle weight.Such recycled polymers may be a mixture of polymers or a single type ofpolymer waste, particularly tailoring for a particular density, such asbelow 1 g/cc or above 1 g/cc, depending upon whether the applicationwould like floating or sinking particles. In addition, the density maybe modified based upon the solidity/vacant volume in the particles. Theplastic particles may have an average largest dimension in a range offrom 5 to 60 mm, e.g., at least 5, 7.5, 10, 12.5, 15, 17.5, or 20 mmand/or up to 60, 50, 45, 40, 35, 30, 25, 20, 17.5, 15, 12.5, or 10 mm.

The filler layers may be packed with the plastic particles, such thatthe geotextile fabric layers require no further structural supportwithin the housing. The plastic particles are not limited in shape, andmay be, for example, spherical, cylindrical prisms, rectangular prisms,triangular prisms, hexagonal prisms, pentagonal prisms, irregularshapes, ovular shapes, elliptical shapes, cubes, etc., or mixtures ofthese.

Inventive water treatment structures may have a weight per volume,without water and without the housing, of no more than 1000, 975, 950,945, 940, 935, 930, 925, 900, 875, 850, 800, 750, 700, 650, 600, 550,500, 450, or 400 kg/m³. For example, inventive structures may have alower density than PP, i.e., 946 kg/m³.

Aspects of the invention provide wastewater treatment systems, which maycomprise any permutation of inventive water treatment structure(s)described herein; and a first separate space, such as an aeration and/oroxygenation tank, separated by a barrier from the fabric layers and thefiller layers, configured to allow an oxygenation of the contaminatedwater. Such a space may take the form of a coil in the pipe leadingwastewater to the upstream inlet and/or a coil in the recycle, and/or atank separate from the piping, wherein the contaminated water and/oreffluent may be treated with oxygen-containing gas(es). The firstseparate space, or portion of the feed and/or recycle, should generallybe sufficient to maintain a dissolved oxygen level of at least 3, 3.25,3.5, 3.75, 4, 4.25, 4.5, 4.75, 5, 5.5, 6, 7, 8, 9, 10, or more mg/L.

Inventive systems may further comprise: a second separate space,separated by a barrier from the fabric layers and the filler layers,configured to collect effluent downstream of the water treatmentstructure. The second separate space may take the form of a dischargetank (9) as depicted in the exemplary drawings, or may be a conicalregion gravitationally below the final layer of the primarydecomposition tank (10), or a collector of some sort in the proximity ofthe final downstream layer of the primary decomposition tank (10), e.g.,fed by a pipe or feed of some sort at the downstream end of the primarydecomposition tank (10).

Inventive systems may further comprise a recycle configured to feedeffluent from downstream of the water treatment structure to a pointupstream of the water treatment structure. The recycle may comprise apipe, a conical portion, e.g., of the base of the housing, an inclinedportion, e.g., at the base of the housing and/or at the downstream end(e.g., final 15, 12.5, 10, 7.5, 5, 2.5, or 1% of the space of thehousing).

Inventive systems may further comprise a septic tank and/or a solidsseparation device, upstream of the water treatment structure. The septictank may take the form of a pre-existing tank which was systematicallyemptied by a municipal and/or commercial service or a body intended toassist in an at least partial decomposition of contaminants inwastewater. A septic tank is not necessary to the inventive system,though at least a device configured to separate off solid matter (e.g.,of longest dimension of at least 2.5, 5, 7.5, 10, 12.5, 15, 17.5, or 20cm) can assist the decomposition of smaller wastewater components.

Inventive systems may further comprise a device configured to removeorganics lighter than water upstream of the water treatment structure.Such devices may take the form of skimmer(s), and/or gravity separators,which may be conical in form. Alternatively, the separators may includecentrifugal components or centrifuges.

Inventive systems system may further comprise an aeration and/oroxygenation device, configured to introduce oxygen into the contaminatedwater upstream of the water treatment structure. Such devices may takethe form of bubblers or other continuous gasification devices, suitableto introduce gas into a liquid stream, e.g., a gas sparger.

Aspects of the invention provide methods for reducing a content of oneor more carbonaceous and/or nitrogenous compounds from contaminatedwater containing the carbonaceous and/or nitrogenous compound(s). Suchmethods may reduce one, several, or all of carbonaceous compounds and/ornitrogenous compounds. Preferably, all such compounds are reduced to atleast below the municipal standards in which the wastewater purificationsystem is located, if not completely eliminate such compounds, e.g.,remove at least 75, 80, 85, 90, 91, 92, 92.5, 93, 94, 95, 96, 97, 97.5,98, 99, 99.1, 99.5, or 99.9 wt. % of a total weight of the carbonaceousand/or nitrogenous compound(s). Such methods may comprise passing acontaminated water, comprising a carbonaceous and/or nitrogenouscompound, at least once sequentially through a first geotextile fabriclayer, a first filler layer comprising plastic particles, a secondgeotextile fabric layer, a second filler layer comprising plasticparticles, a third geotextile fabric layer, etc., to obtain an effluentexiting a final layer, wherein the first filler layer is arrangedbetween the first and second geotextile fabric layers, wherein thesecond filler layer is arranged between the second and third geotextilefabric layers, and wherein the passing reduces a content of thecarbonaceous and/or nitrogenous compound in the effluent, relative tothe contaminated water. The method may comprise 3, 4, 5, 6, 7, 8, . . .15 (or more) geotextile layers including intervening plastic particlelayers and the initial layer may be either a geotextile or a layer ofplastic particles as described anywhere herein.

Inventive methods may further comprise recycling the effluent for asecond, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth . . .cycle of the passing, depending upon the number of layers and/or heightof the column through which the contaminated water passes. For example,if the primary decomposition tank comprises four geotextile layers withintervening plastic particle layers, the system may use 3 recycles (4cycles) to achieve the desired purification, though a column with eightgeotextile layers with intervening plastic particle layers may requireonly two cycles, and a column with 14 to 16 geotextile layers withintervening plastic particle layers may not require any recycling(though such columns may require more vertical and/or cross-sectionalspace). A typical “dual layer” height, i.e., the thickness of ageotextile layer and plastic particle layer, may be, for example, atleast 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, or 4ft and/or up to 6, 5.75, 5.5, 5.25, 5, 4.75, 4.5, 4.25, 4, 3.75, 3.5,3.25, 3, 2.75, 2.5, 2.25, or 2 ft. Correspondingly, a height of anaeration tank and/or discharge tank may be independently, e.g., at least0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.25, or 2.5 ft. and/or up to 4, 3.75,3.5, 3.25, 3, 2.75, 2.5, 2.25, 2, 1.75, or 1.5 ft.

The contaminated water may be oxygenated, e.g., with a sparger and/orwith an aeration or oxygenation tank, to a dissolved oxygen content atleast 3, 3.1, 3.2, 3.333, 3.4, 3.5, 3.6, 3.75, 4, 4.25, 4.5, 5, 7.5, or10 mg/L (or more). The oxygenation may be achieved with air, compressedair, oxygen-enriched compressed air, and/or at least 50, 60, 70, 75, 80,85, 90, 95, 97.5, 98, 99, 99.1, or 99.5 vol. % oxygen.

Inventive systems need not comprise any ceramic, ceramsite, metal (e.g.,steel), rubber, stone, mineral, glass, gravel, sand, quartz sand, filtersand, anthracite, garnet, volcanic rock, zeolite, activated carbon,steel slag, BaSO₄, and/or CaCO₃, within the walls of the decompositiontank, or may comprise no more than 40, 33, 25, 20, 15, 10, 7.5, 5, 4, 3,2, 1, or 0.5 wt. %, relative to the total packing weight, of any ofthese, individually or in combination.

Inventive systems need not comprise any elastomer(s) (e.g., naturalrubber, SBN, polybutadiene, etc.), polymer foam(s) (e.g., polystyrenefoam, polyurethane foam, polyolefin foam, etc.), and/or polystyrene, inthe within the walls of the decomposition tank, or may comprise no morethan 5, 4, 3, 2.5, 2, 1, 0.5, 0.1, 0.01, 0.001, 0.0001, or 0.00001 wt.%, relative to total polymer packing weight, of elastomers, polymerfoam(s), and/or polystyrene, individually or in combination.

Inventive systems need not employ aquatic plants, such as reed, calamus,and canna, or may comprise no more than 5, 4, 3, 2.5, 2, 1, 0.5, 0.1,0.01, 0.001, 0.0001, or 0.00001 wt. %, relative to the total packingcontent weight (excluding wastewater), of such plants, individually orin combination.

Relevant materials for geotextiles and fabrics useful within theinvention, particularly nonwovens may include homopolymers, copolymers,and/or terpolymers (or blends of any of these) of acrylics—such asmethyl methacrylate, methyl acrylate, ethyl methacrylate, ethylacrylate, acrylonitrile, acrylic acid, methacrylic acid, 2-ethylhexylacrylate, hydroxyethyl methacrylate, butyl acrylate, butyl methacrylate,and/or trimethylolpropane triacrylate (TMPTA); olefins—such as ethylene,propylene, 1-butene, isobutene, 1,3-butadiene, isoprene, and/ortetrafluoroethylene; halomonomers—such as vinyl chloride, vinylidenefluoride, tetrafluoroethylene, chlorotrifluoroethylene,hexafluoropropylene oxide, perfluoro(methyl vinyl ether) (CF₂═CFOCF₃),perfluoro(ethyl vinyl ether) (CF₂═CFOCF₂CF₃); vinyl monomers—such asvinyl chloride, 2-chloroethyl vinyl ether, vinyl alcohol, vinylidenedichloride, vinylidene difluoride, and/or vinyl acetate (or otheresters); polyamides—such as polymers of dodecanediamine, decanediamine,octanediamine, hexamethylenediamine, tetramethylendiamine, caprolactam,11-aminoundecanoic, terephthalic acid, 1,5-pentanedioic acid (glutaricacid), 1,6-hexanedioic acid (adipic acid), 1,7-heptanedioic acid(pimelic acid), 1,8-octanedioic acid (suberic acid), 1,9-nonanedioicacid (azelaic acid), 1,10-decanedioic acid (sebacic acid),1,11-undecanedioic acid, 1,12-dodecanedioic acid, 1,13-tridecanedioicacid (brassylic acid), m-xylylenediamine, paraphenylenediamine,terephthalic acid, 1,10-decamethylendiamine, and/or dodecano-12-lactam(lauric lactam), e.g., PA 6 (or nylon 6), PA 12, PA 6,6, PA 6T, PA 1,6,PA 6,9, PA 6,12, PA 11, PA 4,6, PA 12,12, PA 10,10, etc.;polyesters—such as polyethylene terephthalate (PET), polybutyleneterephthalate (PBT), polytrimethylenterephthalate (PTT),polyethylennaphthalate (PEN), polyethylene adipate (PEA), polybutylenesuccinate (PBS), polyglycolic acid (PGA), polylactic acid (PLA),polycaprolactone (PCL), polyhydroxybutyrate (PHB),poly-(R)-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB),poly-3-hydroxyvalerate (PHV),poly(3-hydroxybutyrate-co-3-hydroxyvalerate, polymers of any of themonomers for polyamides with OH substituted for NH₂, and/or Vectranpolyester; polyether ether ketones (PEEK); polyurethanes (PU)—such asPUs comprising polycarbonate(s), polyether(s), and/or polyester(s),and/or toluene diisocyanate (TDI), methylene diphenyl diisocyanate(MDI), 1,6-hexamethylene diisocyanate (HDI),1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane (i.e.,isophorone diisocyanate, IPDI), 4,4′-diisocyanato dicyclohexylmethane,(H₁₂MDI or hydrogenated MDI), polypropylene oxide (PPO), polyethyleneoxide (PEO), poly(tetramethylene ether) glycol, dipropylene glycol,glycerin, sorbitol/water solution, ethylenediamine, triethanolamine,ethylene glycol, 1,4-butanediol (1,4-BDO), 1,6-hexanediol, cyclohexanedimethanol, hydroquinone bis(2-hydroxyethyl) ether (HQEE), ethyleneglycol, diethylene glycol, triethylene glycol, tetraethylene glycol,propylene glycol, dipropylene glycol, tripropylene glycol,1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol,1,4-cyclohexanedimethanol, ethanolamine, diethanolamine,methyldiethanolamine, phenyldiethanolamine, glycerol,trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, pentaerythritol,N,N,N′,N′-tetrakis-(2-hydroxypropyl) ethylenediamine,diethyltoluenediamine, and/or dimethylthiotoluenediamine; and/orpolyimides—such as polymers of pyromellitic dianhydride,4,4′-oxydianiline, benzoquinonetetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, 4,4′-diaminodiphenyl ether (DAPE),meta-phenylenediamine (MDA), and/or 3,3-diaminodiphenylmethane.

Depending upon the application, useful geotextile or particle polymer Mnmay be at least 2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20, 25, 30, 35, 40, 45,50, 65, 75, 85, 100, 125, 150, 175, 200, 250, 350, 500, or 1000 kDaand/or up to 10,000, 5000, 4000, 3500, 3000, 2500, 2000, 1750, 1500,1250, 1000, 900, 800, 750, 700, 650, 600, 550, 500, 400, 300, 200, 175,150, 125, 100, 90, 80, 75, 65, 60, 55, or 50 kDa. Relevant PDIs may varydepending upon application, but will generally be in a range of at least1.05, 1.1, 1.15, 1.25, 1.33, 1.4, 1.5, 1.75, 2, or 2.5 and/or up to 10,9, 8, 7, 6, 5, 4, 3, 2.5, 2.25, 2, 1.75, or 1.5.

Aspects of the invention modify existing synthetic filters to providewater and wastewater treatment systems, occasionally abbreviated hereinby the designation based upon an exemplary embodiment, BioGtex, amongstmany, may be designed to treat wastewater from single homes, businesses,multiple family units, developments, etc., which are not connection to acommunal or municipal sewer system. Inventive water treatment systems,including BioGtex, are generally compact, lightweight, and/orrecirculating packed-bed filters.

Inventive treatment systems may contain 2, 3, 4, 5, 6, 7, 8, 9, 10, ormore layers of nonwoven geotextile fabrics, the fabrics havingindependent thicknesses of, e.g., at least 2, 2.25, 2.5, 2.6, 2.7, 2.75,2.8, 2.85, 2.9, 2.95, 3, 3.05, 3.1, 3.15, 3.2, or 3.25 mm and/or up to5, 4.75, 4.5, 4.4, 4.35, 4.3, 4.25, 4.2, 4.15, 4.1, 4.05, 4, 3.95, 3.9,3.85, 3.8, or 3.75 mm, that may be fixed to one or more walls of thesystem. Inventive treatment systems may include recycled plasticparticles having average particle diameters/largest dimensional sizesof, e.g., at least 7.5, 8, 8.5, 9, 9.25, 9.5, 9.75, 10, 10.25, 10.5,10.75, 11, 11.5, 12, or 12.5 mm and/or up to 25, 24, 23, 22.5, 22, 21.5,21, 20.75, 20.5, 20.25, 20, 19.75, 19.5, 19.25, 19, 18.5, 18, or 17.5mm, packed between the geotextile fabric layer(s), i.e., all layers or80, 75, 67, 60, 50, 40, 33, or 25% of the layers, for example, asexemplified in FIG. 1A.

Inventive water treatment systems, including BioGtex, may be configuredto receive wastewater from, for example, one or more septic tankswhereby the wastewater may have been pretreated to remove larger solidparticles, oil, and/or grease. The wastewater may preferably berecirculated in the inventive systems, including BioGtex, e.g., for atleast 4, 5, 6, 7, 8, 9, or 10 cycles and/or up to 20, 18, 16, 15, 14,13, 12, 11, 10, 9, or 8 cycles, for substantially complete removal oforganics and/or nitrogenous compounds from the waste water, e.g., atleast 75, 80, 85, 90, 91, 92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99,99.1, 99.5, or 99.9 wt. % of a total weight of the organics and/ornitrogenous compounds. Recirculation may ensure sufficient conduct ofthe nitrification process, e.g., oxidation of ammonia, NH₃, and/orammonium ions, NH₄ ⁺, to nitrate ions, NO₃ ⁻, is substantiallycompleted, e.g., at least 75, 80, 85, 90, 91, 92, 92.5, 93, 94, 95, 96,97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. % of a total weight of theammonia/ammonium is oxidized to nitrate.

Inventive systems may implement one or more recirculation pumps, whichmay be selected based on the treatment volume or flux, e.g., of at least50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 750, 1000, 2500, 5000,or more gallons per day and/or up to 20000, 15000, 10000, 7500, 5000,2500, 1000, 750, or 500 gallons per day. Unlike conventional filtersthat use sand or other materials for the treatment media, inventivefilters may use, e.g., no more than 40, 33, 25, 20, 15, 10, 7.5, 5, 4,3, 2, 1, or 0.5 wt. %, relative to the total inorganics and/or treatmentmedium weight, of sand and/or inorganic materials. Inventive systems,including BioGtex may use a geotextile fabric of thickness of, e.g., atleast 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, 4,4.25, 4.5, 4.75, or 5 mm and/or up to 10, 7.5, 7, 6.5, 6.25, 6, 5.75,5.5, 5.25, 5, 4.75, 4.5, 4.25, or 4 mm, and optionally recycled plasticmaterials having diameters or largest dimensions in a range of, e.g., atleast 15, 16, 17, 18, 19, 20, 22.5, 25, 27.5, or 30 mm and/or up to 75,70, 65, 60, 55, 54, 53, 52.5, 52, 51, 50, 49, 48, 47.5, 47, 46, 45 mm,packed between geotextile layers, which geotextile layers may becompact, lightweight, and easy-to-maintain.

Inventive treatment systems including BioGtex may include layeredgeotextiles and (advantageously, recycled) plastic materials configuredto capture influent microorganisms, e.g., capable of capturing at least50, 60, 70, 75, 80, 85, 90, 95, 97.5, 99, or 99.9 wt. % of the influenttotal microorganismic weight. These captured microorganisms can colonizea depth filter and can decompose substrate adsorbed from percolatingwastewater liquid. The practical concern is to provide and sustain highhydraulic capacity by limiting permeability loss, which may be achievedby dispersing biomass within the geotextile fabric(s) and/or on thesurface(s) of the plastic pieces, to maintain aerobic and endogenous(near-starved) conditions. High hydraulic capacity can result in a highlevel of treatment without accumulation of incomplete decompositionproducts. During the operation of inventive systems/BioGtex continuousimprovement in oxygen availability may occur, and/or balancing of theorganic loading and the microorganism population, i.e., thefood-to-microorganism ratio, to mineralize substrate and excess celltissue.

Inventive (e.g., BioGtex) systems may exploit a pattern of dose anddrain methods to gain a number of advantages, one of which is the needfor opportunities for air to reach the biomass and prevent the systemfrom going anaerobic. Our parametric and confirmation studies indicatethat the influent sample should be aerated in the wet well located underthe system before application to an inventive (e.g., BioGtex) treatmentsystem. The parametric variables include the number of geotextile filterlayers, the hydraulic loading rate (HLR), organic loading rate (OLR),organic loading pattern, and provision for passive re-aeration. Incertain treatment systems containing one or more geotextile filters, itis possible to reduce total suspended solids (TSS) and 5-day biochemicaloxygen demand (BOD₅), chemical oxygen demand (COD), total suspendedsolids (TSS), NH₄ ⁺ and the effluent nitrate (NO₃ ⁻), as described inthe doctoral thesis of Cevat Yaman entitled “Geotextiles as BiofilmFilters in Wastewater Treatment,” submitted in the Department ofEnvironmental Engineering at Drexel University, Philadelphia, PA (USA),in 2003, and in J. Environ. Eng. 2005, 131(12), 1667-1675, each of whichis incorporated by reference herein in its entirety.

Aspects of inventive (e.g., BioGtex) systems may provide more compactand/or more predictable treatment generally by biomass distributedthrough layers of porous geotextile filter overlying the plasticmaterials. For example, at least 50, 60, 70, 75, 80, 85, 90, 92.5, 95,97.5, 98, 99, 99.1, 99.5, or 99.9% of the treatment, includingnitrification, may be accomplished before the effluent percolates to thelast layer of geotextile layer. An opportunity for pre-aeration toimprove aerobic biodegradation may be provided at a wet well configuredto receive septic tank effluent.

Aspects of the invention include processes involving: removing suspendedmaterial from the influent; growing an active biomass within thefabric(s) and/or on the surface(s) of the plastic pieces; biodegrading,in-place, filtered and adsorbed organic material to full mineralization,i.e., at least 90, 91, 92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99, 99.1,99.5, 99.9, 99.99, or 99.999%, up to 100%, mineralization.

Aspects of the invention control and modulate the biomass distribution.The inventors have found that only certain nonwoven geotextiles canprovide satisfactory biomass hosting. Certain continuous filament typeof needle-punched nonwovens have shown excellent performance fortreating biomass, and aspects of the invention employ one or more ofsuch nonwovens. The “treating” biomass, i.e., the biomass suitable todecompose organics and nitrogenous compounds in wastewater, generallyderives from microorganisms in the influent. Scanning electronmicroscope (SEM) analysis has shown treating biomass to form adiscontinuous plate-shaped floc within the pores of the geotextile. Thebiomass is generally actually a captive, suspended growth rather than anattached growth, fixed to a medium with one-dimensional substrate andoxygen transfer only. Via adhesion as a suspended growth a desired levelof contact between biomass and substrate can be reached withoutsignificantly reducing permeability. The biomass can grow and mature tointernally provide a sequence of biochemical reactions, includingdecomposition of carbonaceous constituents and conversion of ammoniaand/or ammonium to nitrate.

Relevant nonwovens, especially needle-punched nonwovens, may includefibers or filaments (re)oriented into a (vertical) direction orthogonalto the plane of the geotextile, and/or with no chemical/adhesivebonding, no thermal bonding, no bonding of spunlaid webs, etc. Usefulgeotextiles may be described in Advances in Technical Nonwovens G.Kellie (ed.), London: Woodhead, 2016; Sustainable Fibres and Textiles,S. S. Muthu (ed.), London: Woodhead, 2017; Applications of Nonwovens inTechnical Textiles, R. A. Chapman (ed.), London: Woodhead, 2010; ProcessControl in Textile Manufacturing, A. Majumdar et al. (eds.), London:Woodhead, 2013; each of which is incorporated by reference herein in itsentirety. Useful geotextiles may be made without saturation adhesivebonding, spray adhesive bonding, foam bonding, powder application, printbonding, discontinuous bonding, hot calendering, belt calendering,through-air thermal bonding, ultrasonic bonding, and/or radiant heatbonding.

Needle-punched nonwovens may be made by punching with, e.g., at least3000, 3500, 3750, 4000, 4250, 4500, 4750, 5000, 5250, 5500, 5750, 6000,6250, or 6500 needles/m² and/or up to 10000, 9500, 9000, 8500, 8000,7750, 7500, 7250, 7000, 6750, 6500, 6250, 6000, 5750, 5500, 5250, or5000 needles/m². The punch density may also be, e.g., at least 25, 35,40, 45, 50, 55, 65, 75, 85, 100, 125, or 150 punches/cm² and/or up to500, 450, 425, 400, 375, 350, 325, 300, 275, or 250 punches/cm².Needle-punched filters useful within the scope of the invention may havea mass per surface area of, e.g., at least 25, 35, 50, 65, 75, 100, 125,150, 175, 200, 225, 250, 300, 350, or 500 g/m² and/or up to 3000, 2750,2500, 2250, 2000, 1750, 1500, 1250, 1000, 750, 500, 250, 200, or 150g/m². Useful geotextiles may have a thickness of, e.g., at least 0.25,0.33, 0.4, 0.5, 0.75, 0.85, 1, 1.25, 1.5, 2, 3, 4, or 5 mm and/or up to20, 17.5, 15, 12.5, 10, 9, 8, 7, 6, or 5 mm. Useful geotextiles may havea bulk density of, e.g., 0.04, 0.045, 0.05, 0.055, 0.06, 0.065, 0.07,0.075, 0.08, 0.085, 0.09, 0.095, or 0.1 g/cc and/or up to 0.2, 0.175,0.15, 0.14, 0.13, 0.125, 0.12, 0.115, 0.105, 0.1, 0.095, 0.09, 0.085, or0.08 g/cc. Air permeabilities of relevant geotextiles may be, forexample, at least 50, 55, 60, 62.5, 65, 67.5, 70, 72.5, 75, 77.5, or 80m³/m²/min and/or up to 200, 175, 150, 135, 125, 115, 110, 105, 100, 95,90, 87.5, 85, 82.5, or 80 m³/m²/min. Sectional air permeabilities ofrelevant geotextiles may be, for example, at least 0.08, 0.1, 0.12,0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.3m³/m/min and/or up to 0.4, 0.38, 0.36, 0.34, 0.32, 0.31, 0.3, 0.29,0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, or 0.2 m³/m/min. Usefulfabrics may have a linear mass density of fibers of, e.g., 1, 2, 3, 4,5, 6, 7, 8, 9, or 10 denier and/or up to 15, 14, 13, 12, 11, 10, 9, 8,7, or 6 denier. Relevant geotextiles may have constituent fiberdiameters in a range of from, e.g., at least 5, 6, 7, 7.5, 8, 8.5, 9,9.5, 10, 10.5, 11, 11.5, 12.5, or 15 μm and/or up to 100, 85, 75, 65,55, 50, 45, 40, 35, 30, 25, 20, 17.5, 15, 12.5, or 10 μm. Relevantgeotextiles may have cut fiber lengths in a range of from, e.g., atleast 8, 10 12, 13.5, 15, 16, 17, 18, 19, 20, 21, 22.5, or 25 and/or upto 100, 75, 65, 50, 45, 40, 35, 32.5, 30, 27.5, 25, 22.5, or 20 mm.Relevant geotextiles may have volume densities of constituent fibers(according to ASTM C693) in a range of from, e.g., at least 1000, 1250,1500, 1750, 2000, 2250, 2500, 2600, 2700, 2800, 2900, or 3000 g/cm³and/or up to 8000, 7500, 7000, 6500, 6000, 5500, 5000, 4500, 4250, 4000,3750, 3500, 3250, or 3000 g/cm³. Any of these endpoints mayalternatively apply as upper or lower endpoints, depending upon thedesired application.

Well-designed layered geotextile systems can be superior to conventionalonsite systems in reducing the two basic secondary treatment indicators,total suspended solids (TSS) and 5-day biochemical oxygen demand (BOD₅),and in nitrifying and partially denitrifying the effluent. Aspects theinventive include economic and feasibly engineerable/manufacturableapplication of water treatment systems, e.g., BioGtex, to onsitesystems, allowing the infiltration area required to treat a givendischarge, i.e., the sustainable hydraulic loading rate. Thesustainability may be expressed in terms of permeability, which maycorrelate to maintaining the biomass in an endogenous state anddecomposing organic byproducts. The organic loading rate (OLR) is arelevant feature, which can be modified in aspects of the invention,e.g., to be consistent with the oxygen supply rate. The organic loadingrate (OLR) is generally proportional to the hydraulic loading rate(HLR).

A general use of inventive (e.g., BioGtex) systems is exemplified in theFIG. 2 . Inventive (e.g., BioGtex) systems may be designed to treatwastewater from a 3-bedroom single house. A common design flow rate of150 gal/day/bedroom may be used, as well as, for example, at least 100,110, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, and 175gal/day/bedroom and/or up to 300, 275, 250, 225, 200, 175, 165, 160,155, 150, 145, or 140 gal/day/bedroom. Therefore, for example, a designflow rate of 450±5, 10, 15, 20, 25, 33, 40, 50, 67, 75, or 100 gal/dayfor a 3 bedroom house may be used. Smaller and larger flow rates may beused for. Inventive (e.g., BioGtex) systems may be operated withhydraulic loading rate (HLR) of 5 gal/day/ft², which means for eachsquare foot of treatment unit surface, 5 gallons of wastewater will beapplied per day. For example, inventive systems may have HLRs of atleast 1, 2, 3, 4, 4.5, 4.75, 5, 5.25, 5.5, 5.75, 6, 7.5, 10, 25, or 50gal/day/ft² and/or up to 500, 400, 300, 250, 200, 150, 100, 75, 50, 25,10, 9, 8, 7, 6, 5.5, 5, 4.75, 4.5 gal/day/ft².

For an exemplary system based on a design flow rate of 450 gal/day, across sectional area required is 90 ft², based on calculations usingEquation 1, below:

A=Q/HLR  Eq. 1,

in which A is area, Q is design flow rate, and HLR is hydraulic loadingrate (450 gal/day/5 gal/day/ft²=90 ft²). For a circular cross-sectionwater treatment system, relying on the area of a circle being πr², thediameter (2r), a diameter of a cylindrical geotextile biofilter unit canbe calculated to be 10.7 ft, i.e., 90=π×D²/4=D=10.7 ft.

Aspects of the invention may offer advantages over existing septiceffluent treatment systems, including, for example: (1) removingcarbonaceous and/or nitrogenous compounds at a higher level, e.g., 1.1,1.2, 1.25, 1.33, 1.4, 1.5, 1.75, 2, 2.5, 3, 3.5, 5-fold or more, due tothe availability of higher surface area, which may be provided by theinserted geotextile filter and the recycled plastic filling material;(2) enhancing biofilm growth in higher amounts and/or rates, and helpingremove carbonaceous and nitrogenous compounds at higher rates, likelydue to such higher surface areas (compared to conventional sandfilters); (3) reducing and/or eliminating clogging due to biomass orsuspended solid accumulation, possibly attributable to the higherporosity of filling materials in inventive (e.g., BioGtex) systemscompared to sand filters; (4) allowing the use of increased hydraulicloading rates, e.g., at least 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7.5, ormore gal/day/ft², relative to conventional sand filters (around 1 to 2gal/day/ft², due to solids, biomass, and byproduct accumulation in thepores); (5) facilitating the operation and maintenance of inventivesystems relative to known systems, as shown in FIG. 3 ; (6) allowingand/or simplifying replacement of one or more filter/system components,such as the geotextiles, the plastic filling materials, etc.; (7)simplifying transport and/or handling and sinking cost of the materials,e.g., allowing the use of geotextile and/or optionally recycled plasticfilling material, which are lightweight compared to sand filtermaterials, e.g., sand, gravel, etc.; (8) improving the accuracy and/orpredictability of water treatment performance in terms of effluentquality indicators, such as TSS, BOD₅, NH₃, TN, and/or TP, usingconventional wastewater treatment indices (F/M ratio, etc.) relative tocustomary systems; (9) improving economy and physical feasibility ofwastewater treatment by increasing the hydraulic loading rate relativeto known systems; and/or (10) increased reliability via more assuredoxygen supply and mineralization of carbonaceous and/or nitrogenousmaterial to avoid solids accumulation, relative to known systems.

The removal rates for carbonaceous and nitrogenous compounds in themethod and system of the present disclosure are greater than around 97and 90%, respectively, preferably greater than 98 and 95% or greaterthan 99 and 98%. Even at very high hydraulic loading rates (HLR), forinstance at HLR of 100 gal/ft²·day, it is possible to meet the goal ofeffluent BOD₅ below 10 mg/L. Up to 90% of the NH₄ can be converted toNO³⁻. This does not close the nitrogen mass balance. Nitrate is aconcern in groundwater at concentrations above 10 mg/L, and it is also anutrient that can cause eutrophication in receiving waters. Therefore, acomplete conversion of NO³⁻ to N₂ gas within the BioGtex system ispreferred. However, anaerobic environment is needed for the conversionof NO³⁻ to N₂ gas. BioGtex is mainly an aerobic system, however, as thebiofilm layer thickens in the BioGtex geotextile/plastic particle media,an inner anaerobic layer can form, at which point some denitrificationwill occur in the geotextile and plastic particle comprising containers,which may provide complete nitrogen removal.

Aspects of the invention may provide water (e.g., BioGtex) treatmentsystems which improve over known systems in using easier to transport,less expensive, and/or easier to handle system materials, e.g., withcomponents of lightweight materials. Aspects of the invention mayinclude sufficient oxygen supply and/or flux such that leachate chemicaloxygen demand (COD) of 100,000 mg/L, i.e., approximately 100 timeshigher than the COD of septic effluent, does not clog geotextile filtersafter 1.5, 2, 2.5, 5, 7.5, 10, 15 or 20 years in use.

Inventive water treatment systems may include a reactor space filledwith (optionally recycled) plastic materials. Inventive water treatmentsystems may include 3, 4, 5, or more layers of nonwoven geotextilefilters, which may be independently placed vertically, diagonally (e.g.,15, 30, 45, 60, or 75°), or horizontally relative to the direction ofgravity. Inventive water treatment systems may recirculate/recyclewastewater 4, 5, 6, 7, 8, 9, 10 or more times per each volume ofwastewater treated. Inventive water treatment systems may provide aspace for wastewater to be stored, e.g., a tank that may be under thesystem, wherein the wastewater may be aerated before it is fed to thesystem. Treated wastewater may be filtered by gravity and/or withpump(s) to the pre-treatment space/tank and be mixed with the storedwastewater. After completing the recirculation cycles, the treated wateris discharged into nearby water body, such as surface water, acreek/river, a sea, an ocean, etc.

BioGtex systems may be intended for the treatment of wastewater from asingle house that generates, for example, 450-gal wastewater per day.The wastewater may be generated from both bathroom(s) and the kitchen. Atypical effluent volume for a 3-bedroom house is around 450 gal (ca.1703 L) of wastewater. The wastewater may first be discharged into acontainer, such as a septic tank, where the solid particles can settleto the bottom of the tank or be filtered off at, e.g., the outlet of thetank. Oil and grease can be trapped by oil traps and skimming devicesplaced on the top of the septic tank. The wastewater feeding a BioGtexsystem may be substantially or completely free of large solid particles,oil, and grease. Total suspended solids (TSS), organic compounds (BOD₅),and nitrogenous compounds (NH₄—N) may be removed in BioGtex systems.

Layered geotextile fabrics and plastic materials, including recycledplastic materials, are able to capture and/or adsorb, at leasttemporarily (i.e., for 4, 8, 10, 12, 16, 18, 24, 48, 72, 92, or morehours), influent microorganisms. Captured microorganisms grow onsurface(s) of the plastic particles and/or form a depth filter in thegeotextile fabric, and such surfaces and/or depth filters can decomposesubstrates adsorbed from percolating wastewater liquid. Aspects of theinvention may provide and sustain high hydraulic capacity by limitingpermeability loss, e.g., by dispersing biomass within the geotextilefabric and/or on the surface(s) of plastic particles, to maintainaerobic conditions. Limited permeability loss can result in a thoroughwastewater treatment, i.e., decomposition of at least 75, 80, 85, 90,92.5, 95, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. % of decomposablematter, nitrogenous wastewater compounds, and/or carbonaceous wastewatercompounds, without accumulation of incomplete decomposition products.Inventive systems, such as BioGtex, can continuously improve oxygenavailability in operation and can balance organic loading with themicroorganism population to mineralize substrates and excess celltissue.

Inventive (e.g., BioGtex) systems can employ a pattern of dose and drainmethods, including allowing air to reach the biomass and prevent thesystem from going anaerobic. Parametric and confirmation studies haveindicated that aeration of the influent sample, e.g., in an aerationtank located, to the side of, under, or over the filter system, beforeintroduction to inventive treatment systems, can aid filtration anddecomposition. Such parametric variables include the properties of thegeotextile fabrics and the plastic particles, hydraulic loading rate(HLR), and organic loading rate (OLR). Inventive treatment systemscontaining geotextile fabrics, make it possible to achieve over 90, 91,92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. %removal of total suspended solids (TSS), 5-day biochemical oxygen demand(BOD₅), and/or NH₄—N, individually or cumulatively.

Inventive water treatment systems, such as BioGtex systems, can becharacterized by lightweight, compact, and cost effective design,removal of organic and nitrogenous compounds from wastewater, resistanceto clogging due to wastewater percolation, long-term uninterruptedoperation, simplified operation and maintenance, microorganism growth onsurfaces of geotextile fibers and plastic particles (i.e., attached,adhered, and/or adsorbed growth), and/or microorganism growth insuspension in the pores of the geotextile fibers, i.e., suspended and/orunattached growth.

Properties of Geotextile Fabric

Geotextile fabrics for drainage and filtration materials have been usedin geotechnical and geo-environmental engineering for decades. Thefunctions of geotextile fabrics include drainage, filtration, andseparation. Nonwoven geotextiles are very permeable materials.Therefore, the water permeability of geotextile fabrics normal to theplane is an important parameter that can be used in application. Usefulgeotextile fabrics in inventive systems, such as BioGtex systems,include highly porous, allowing water to flow through while containingcoarse particles. The chemical composition of the geotextile fabricuseful for inventive systems may be polymers of, e.g., olefins, such asethylene, propylene, isobutylene, 1-butene, butadiene, neoprene, etc.,styrene, fluorinated monomers, such as tetrafluoroethylene, vinylidenedifluoride, hexafluoropropylene, octafluoroisobutene,chlorotrifluoroethylene, etc., and/or condensation polymers of, e.g.,ethylene glycol, butylene glycol, ethylene diamine, ethanolamine,hexamethylene diamine, p-phthalic acid, adipic acid, caprolactam,paraphenylenediamine, dodecanediamine, ω-aminolauric acid, etc. Forexample, polyethylene (PE) and polypropylene (PP) are a thermoplasticpolyolefin material which can have several different polymer chainstructures depending on the polymerization conditions. Copolymers ofethylene and propylene (or other polymers) and compounds of homopolymersare also relevant, depending upon the application.

Pore size in relevant geotextile fibers described herein relate to thevoid space between geotextile fibers or apparent opening size (AOS). TheAOS of relevant geotextile fabrics in inventive systems is notparticularly limited and may be, for example, between 80 and 100 USsieve, e.g., at least 70, 72, 74, 76, 78, 80, 82, 84, 85, 86, 87, 88,89, or 90 US sieve and/or up to 110, 108, 106, 104, 102, 100, 98, 96,95, 94, 93, 92, 91, or 90 US sieve, or between 0.15 and 0.18 mm (ASTMD4751), e.g., 0.1, 0.11, 0.12, 0.125, 0.13, 0.135, 0.14, 0.1425, 0.145,0.1475, 0.15, 0.1525, 0.155, 0.1575, or 0.16 mm and/or up to 0.22, 0.21,0.205, 0.2, 0.195, 0.19, 0.1875, 0.185, 0.1825, 0.18, 0.1775, 0.175,0.17, or 0.165 mm.

Useful geotextile fabrics may have a porosity of, e.g., at least 0.65,0.675, 0.7, 0.725, 0.75, 0.76, 0.77, 0.775, 0.78, 0.79, 0.8, 0.81, 0.82,0.825, or 0.85 and/or up to 0.975, 0.97, 0.96, 0.95, 0.94, 0.93, 0.925,0.92, 0.91, 0.9, 0.89, 0.88, 0.875, 0.87, 0.86, or 0.85.

Useful geotextile fabrics may have a thickness of, e.g., at least 2,2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.75, 2.8, 2.9, 3, 3.1, 3.2, or 3.25mm and/or up to 5, 4.9, 4.8, 4.7, 4.6, 4.5, 4.4, 4.3, 4.25, 4.2, 4.1, 4,3.9, 3.8, 3.75, 3.7, 3.6, or 3.5 mm.

Useful geotextile fabrics may have a permeability of, e.g., at least 2,2.25, 2.5, 2.6, 2.7, 2.75, 2.8, 2.85, 2.9, 2.9, 3, 3.05, 3.1, 3.15, 3.2,3.25, 3.3, 3.4, 3.5, 3.75, or 4×10⁻³ m/s and/or up to 7, 6.75, 6.5, 6.4,6.3, 6.25, 6.2, 6.15, 6.1, 6.05, 6, 5.95, 5.9, 5.85, 5.8, 5.75, 5.7,5.6, 5.5, 5.25, or 4×10⁻³ m/s.

Useful geotextile fabrics may have a puncture resistance of, e.g., atleast 0.2, 0.205, 0.21, 0.215, 0.22, 0.225, 0.23, 0.235, 0.24, 0.245,0.25, 0.26, 0.275, 0.3, 0.325, or 0.35 kN and/or up to 0.65, 0.625, 0.6,0.575, 0.57, 0.56, 0.55, 0.54, 0.53, 0.525, 0.52, 0.515, 0.51, 0.505,0.50, 0.495, 0.49, 0.485, 0.48, 0.475, 0.45, 0.425, or 0.4 kN.

Useful geotextile fabrics may have a trapezoid tear strength of, e.g.,at least 0.15, 0.155, 0.16, 0.165, 0.17, 0.175, 0.18, 0.185, 0.19,0.195, 0.2, 0.21, 0.225, 0.25, 0.275, or 0.3 kN and/or up to 0.51, 0.5,0.495, 0.49, 0.485, 0.48, 0.475, 0.47 kN.

Useful geotextile fabrics may have a mass per unit area of, e.g., atleast 150, 175, 185, 190, 195, 200, 205, 210, 215, 220, 225, 235, or 250g/m² and/or up to 450, 425, 420, 415, 410, 405, 400, 395, 390, 385, 380,375, 367, or 350 g/m².

Useful geotextile fabrics may preferably comprise polypropylene and/ormay be of, e.g., a polymer type of nonwoven needle-punched continuousfilament or nonwoven needle-punched stapled fiber. Nonwoven geotextilesare useful materials for the growth of biomass on their surfaces, intheir pore spaces, on the fibers, and/or in suspension between the fibercages. Nonwoven geotextile fabrics can perform well for thebiodegradation of organics present in the infiltrating wastewaterthrough the geotextile fabric.

Properties of Plastic Particles Used in Biogtex

Plastic particles useful in inventive (e.g., BioGtex) water treatmentsystems may be made from a polyolefin, such as polyethylene,polypropylene, neoprene, polybutadiene, etc, at discussed above, or apolyester (PET, PTT, PBT, polylactic acid, polyglycolic acid, PEA, PBS,PHB, PCL, etc.), polyamide (e.g., nylon 6, nylon 6,6, nylon 12, etc.),polystyrene, ABS, silicone rubbers, SBN rubbers, polyurethanes,fluoroelastomers, PTFE, PVDF, etc. Such particles may comprise compoundsof any of these, and/or copolymers of these. The materials in usefulparticles may be surface-treated, e.g., to comprise surface OH, COOH,CONH₂, and/or —NR₂ groups.

Relevant plastic particles may have an average diameter or averagelargest dimension of, e.g., at least 7, 8, 9, 10, 11, 12, 13, or 14and/or at least 25, 24, 23, 22, 21, 20, 19, 18, or 17 mm, with a densityof, e.g., at least 25, 27.5, 30, 32.5, 35, 37.5, 40, 42.5, 45, 47.5, 50,52.5, 55, 57.5, or 60 kg/m³ and/or up to 125, 120, 125, 110, 107.5, 105,102.5, 101, 100, 99, 98, 97.5, 97, 96, 95, 94, 93, 92.5, or 90 kg/m³.Plastic particles useful within the scope of the invention may beprepared from e.g., at least 50, 60, 70, 75, 80, 85, 90, 95, 97.5, or100 wt. %, recycled materials.

Useful plastic particles may be prepared as a cylindrical (from plate torod shaped), spherical, triangular prismic, rectangular (incl. square)prismic, hexagonal prismic, and/or oval shape with a capability ofgrowing biomass on their surfaces. The void fraction of the plasticparticles with respect to total particle volume may be adjusted to makespace available for biofilm growth and water and air circulation.Generally, the greater the organic load applied, the higher the porositymust be, as the biofilm will be thicker. Plastic particles useful ininventive water treatment systems may have a high surface area formicrobial biofilms per unit volume, e.g., void ratios of at least 85,87.5, 90, 91, 92, 93, 94, 95, 96, 97, or 97.5%. Void ratios of above 75%can be useful to maintain efficient oxygen delivery to themicroorganisms and drive efficient performance. The specific surfacearea of the plastic particles available for the biofilm development perunit bed volume may be, for example, at least 85, 90, 95, 100, 105, 110,115, 120, or 125 m²/m³ packing material and/or up to 200, 190, 180, 175,170, 165, 160, 155, or 150 m²/m³ packing material. Either or both of thegeotextile fabrics and the plastic particles may allow for the growth ofbiomass on their surfaces, i.e., plastic particle(s) and/or geotextilefabric(s), and in their pores, particularly the geotextile fabric(s), tothereby biodegrade organics present in the wastewater being treated.Plastic particles may be cleaned before use in inventive waterpurification systems, but generally need only be sterilized towards thebacteria necessary to conduct the relevant decompositions.

Pretreatment of Wastewater in a Septic Tank

The composition of the wastewater coming to one or more septic tanks (orother pre-storage tanks) of the inventive water treatment system may bea mixture of greywater originating from kitchens, washing machines,showers, etc., and blackwater originating from toilets. Pretreatment ofwastewater in the septic tank may remove, for example, solidcontaminants from the wastewater to prepare the effluent for finaltreatment and discharge into the environment. A septic tank orpre-treatment storage container/reservoir in inventive systems willgenerally be an enclosed watertight container that provides pretreatmentof wastewater by separating solids, and optionally further oil and/orgrease. Other separative pre-treatment mechanism in the art may also beused. Removal of the solids, e.g., by slowing down the wastewater flowand allowing the solids to settle to the bottom of a pre-treatment tank,while allowing fats, oils, and greases to rise to the surface of thewater. A retention time of, e.g., at least 18, 24, 30, or 48 hours mayrequired for the solids to settle. At least 25, 33, 45, 47.5, 50, 52.5,55, 60, or 65% of the settled solids may undergo decomposition while therest will generally accumulate as sludge at the tank bottom and mayrequire removal by other means.

Fats, oils, and grease, originating from animal and vegetable sources,can clog wastewater pipes and treatment systems. Separators and/orskimmers for fats, oils, and greases can remove most (independently 85,90, 92.5, 95, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. %) or all thesubstances having a density less than water, insofar as such substancesare not dissolved or solubilized in the aqueous phase. Oils and greaseare preferably removed in a septic tank or pre-treatment, i.e., beforereaching the decomposition portion of inventive water treatment systems,because oils and greases can cause problems in the treatment process.Inventive systems preferably include at least one oil and greasetrap/skimmer (20) placed in the septic tank (1) as shown in FIG. 1 .

An effluent filter (21) may be placed at the outlet of the septic systemto remove solids in the septic tank (1) from exiting into thedecomposition stage (containing outlets 3 and 6 to 15) of inventivesystems. The effluent filter (21) may be made of slotted plastic, glass,or metal, to allow the liquid to pass through and restrain largersolids.

Distribution of Biomass

Attached growth, in which biofilm coats a solid media, is lessmechanically complex and often more robust with respect to varyinghydraulic and substrate loadings. As the surface of the biofilmincreases, more organics can be adsorbed from the wastewater, and athick biofilm can provide more diverse microorganisms to biodegradecarbonaceous and nitrogenous constituents.

One of the methods for bringing biomass and substrate into contactincludes filtration and tangential flow, typically used in biofilters.Inventive systems can assure intimate contact when the wastewaterpermeates through geotextile fabric (8) and the plastic particles (12).In tangential contact, wastewater will flow over the biofilm coatinggeotextile fibers and the plastic particles. The thickness of thebiofilm on the geotextile fibers and the plastic particles can becontrolled by the hydraulic loading rate (HLR) to optimize substratetransfer. Once the biomass reaches a certain thickness, it can sloughoff the media.

Biomass also exists as a free floc, dispersed unattached/unadheredthrough the pores of the geotextile fibers. Wastewater can flow freelythrough porous biofilms and around the free floc. Such contact betweenthe biomass and the substrate can be referred to as a captive suspendedgrowth system.

Needle-punched geotextiles can have sufficient interior porosity toavoid clogging at the surface generally known to geotextiles when excesssuspended solids block the entry pores. Needle-punched nonwovengeotextile fabrics can promote biomass growth mostly in the interior,rather than on the surface.

Biomass growth and distribution can also be modified via the specificsurface area of the geotextile fabric and the plastic particles, i.e.,surface-to-volume relationship. Surface areas and internal porosities ofgeotextile fabrics and plastic particles as described above, can allowfor useful amounts of biomass growth to maintain satisfactory fluxconditions. FIG. 3 depicts an exemplary arrangement of a nonwovengeotextile (here having a thickness of 3 to 4 mm) soaked withwastewater, including a scaled-up representation of individual fibers ofthe nonwoven geotextile with attached growth on the fibers and suspendedgrowth within the porous between the fibers. As seen in FIG. 3 , adominant mechanism of biomass growth in inventive treatment systems maybe in the form of fixed-film, i.e., the attached growth on the fibersdepicted on the zoomed-in exemplary representation on the bottom rightof FIG. 3 .

Inventive (e.g., BioGtex) water treatment systems can also havesuspended growth. Attached growth generally takes place on the surfaceof the geotextile fabric(s), plastic particles, and geotextile fibers.When wastewater, e.g., from a septic tank or other pre-treatment, is fedinto an inventive water treatment system, a layer of biomass willtypically form on the surface of the geotextile fibers and plasticparticles, e.g., having a thickness of at least 10, 25, 50, 100, 250,500, 750, 1000, 1750, 2000, 2250, 2500, 2750, 3000, 3250, 3333, or 3500μm and/or up to 7.5, 6.67, 6, 5.5, 5.25, 5, 4.75, 4.67, 4.6, 4.5, 4.4,4.33, 4.25, 4.15, 4, 3.85, 3.75, 3.67, 3.6, 3.5, 3.4, 3.33, 3.25, 3.15,3, 2.9, 2.8, 2.75, 2.67, 2.6, or 2.5 mm. After long-term wastewaterapplication to inventive systems, a thickened layer of biofilm willdevelop on the surface of geotextile fibers and plastic particles. Asubstantially continuous biofilm layer adhering to the geotextile fibersand plastic surfaces will typically develop. Increased biomass growthwill thicken the biofilm and encroach on the liquid transport channels.Maintaining even distribution of the wastewater on the surface ofgeotextiles and/or plastic particles can allow even growth of biomass onthe surface of the geotextile fibers and plastic particles. As thebiofilm layer thickens in/on the geotextile fibers and plasticparticles, an inner anaerobic layer will generally form. Customarythicknesses of such inner anaerobic layers can be, for example, at least5, 10, 15, 25, 30, 35, or 40% and/or up to 65, 60, 55, 50, 45, 40, ofthe attached growth layer thickness. Once the anaerobic layer is formed,some denitrification can occur in inventive systems, which can providecomplete nitrogen removal, e.g., at least 75, 80, 85, 90, 91, 92, 92.5,93, 94, 95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. %—or all—ofthe oxidizable nitrogen-containing compounds in the resident wastewater,depending on its thickness relative to flow and/or activity.

The treating biomass generally forms a discontinuous plate-shaped flocwithin the pores of the geotextile. The biomass is typicallysubstantially (e.g., at least 50, 60, 70, 75, 80, 85, 90, or 95 wt. % ofthe biomass) a captive suspended growth rather than an attached growth,fixed to a media with one-dimensional substrate and primarily to onlyconducing oxygen transfer. The substantially unattached state of biomasscan provide sufficient contact between the biomass and the substratewithout significantly reducing permeability.

The biomass can grow and mature in an unattached (or attached) state inthe inventive systems to internally provide a sequence of biochemicalreactions, including decomposition of carbonaceous constituents,generally to gaseous products, such as CO₂ and H₂O, and conversion ofammonia/ammonium ions to nitrate.

Exemplary cross-sectional view representations of the biomass growth ininventive geotextile fabric and plastic particle arrangements are shownin FIG. 3 and FIG. 4 . Geotextile fabrics can typically support morebiomass compared to other filter media used in the art. Biomass ingeotextile fabrics can calculated or quantified in grams volatilesuspended solids (VSS) per m² of the fabric material. Inventive (e.g.,BioGtex) systems may have a mass of biomass of, for example, at least70, 72.5, 75, 76, 77, 77.5, 78, 78.5, 79, 79.5, 80, 80.5, 81, 81.5, 82,82.5, 83, 83.5, 84, 84.5, or 85 g/m² and/or up to 125, 120, 115, 112.5,110, 107.5, 1050, 104, 103, 102.5, 102, 101.5, 101, 100.5, 100, 99.5,99, 98.5, 98, 97.5, 96, 95, 92.5, 90, 87.5, or 85 g/m² of geotextilefabric. Useful geotextile fabrics are not generally limited inthickness, but may be thin, e.g., at least 2, 2.25, 2.5, 2.75, 3, 3.25,3.5, 3.75, or 4 mm and up to 10, 9, 8, 7, 6, 5.5, 5, 4.5, 4.25, 4, 3.9,3.8, 3.75, 3.7, 3.65, 3.6, 3.55, 3.5, 3.45, 3.4, 3.35, 3.3, 3.25, 3.2,3.15, 3.1, 3.05, or 3 mm. Thus, biomass density unit of gram biomass perm² of geotextile fabric a relevant evaluation. Converting g/m² to g/m³,the biomass density in geotextile fabric can be, for example at least10, 11, 12, 12.5, 13, 13.5, 14, 14.5, or 15 kg biomass/m³ of geotextilefabric, and up to 25, 22.5, 20, 17.5, 17, 16.5, 16, 15.5, 15, or 14.5 kgbiomass/m³ of geotextile fabric. Such values compare well to otherfilter materials such as sponge (3 to 6 kg/m³), zeolite (0.044 to 0.090kg/m³) and ceramsite sand (0.107 to 0.214 kg/m³).

Distribution of Oxygen

Sufficient aeration of the wastewater can provide the required dissolvedoxygen (DO) for the biochemical oxidation to degrade organic compoundsand to enhance nitrification of ammonia and/or ammonium ions. Aerationof the influent wastewater can take place, for example, in an aerationtank located underneath, to the side of, above, or even remote to (e.g.,within 10, 5, 2.5, 1, 0.5, 0.25, 0.1, 0.075, 0.05, 0.025, 0.01, or 0.005km) the inventive geotextile/particle tank system. Aeration can beachieved by an air blower, bubbler, pump, or the like, then the effluentmay be pumped to the top of the inventive BioGetx system for gravityfiltration downward.

Dissolved oxygen concentration may be measured in the aeration tank tomake sure that the DO levels are never below, e.g., 2.75, 3, 3.25, 3.5,3.55, 3.6, 3.65, 3.7, 3.75, 3.8, 3.85, 3.9, 3.95, 4, 4.05, 4.1, 4.15,4.2, 4.25, 4.5, 4.75, 5, 5.25, 5.5, 5.75, 6, 7, 8, 9, or 10 mg/L, evenmaintaining the wastewater at a saturated oxygenation level, e.g., 99.9,99, 95, 90, 85, 80, 75, 65, 50, 40, 33, 25, or 10% O₂ saturated. Oxygenenriched effluent wastewater may be evenly distributed over theinventive geotextile/plastic particle decomposition system by using oneor more perforated distribution pipes located at the top of the system.During the resting, residence, or incubation time between recirculationsets, air may be circulate between the geotextile fibers and the plasticparticles, allowing oxygen diffusion into the biofilm to provideadditional oxygen to the biofilm.

Permeability

The hydraulic performance of inventive systems generally depends onoperating conditions, such as hydraulic loading rate (HLR), organicloading rate (OLR), and oxygen supply. Since most of the solid particlescan be removed in a pre-treatment device/container and/or septic tank,permeability loss or clogging in geotextile fabric may be primarily dueto biomass growth. However, as described above, the biofilm growthbetween geotextile fibers is typically from inside the nonwoven outwards(i.e., to the outer surfaces of the nonwoven), leaving enough space forliquid flow in the porous nonwoven geotextile structure. In addition,excess substrate and biomass cells may be digested during therest/residence periods, which may open up, e.g., 50, 60, 70, 75, 80, 85,90, or 95% of, clogged pores between the fibers.

Recirculation

The number of cycles, i.e., recirculation number, for each volume ofwastewater treated may be, for example, 8 counts, or at least 4, 5, 6,7, 8, 9, 10, or 11 cycles and/or up to 20, 18, 26, 14, 13, 12, 11, 10,9, or 8 cycles, which—in the case of 8 cycles—means that each volume ofwastewater will be filtered through the inventive system 8 times beforeits final discharge. Recirculation number can be increased or reduced,depending on the treatment efficiency and/or water quality desired.Inventive processes may be set up as batch processes flow processes, ormixtures of these, so that the cycle counts may be “theoretical”decimals of any of the cycle counts discussed, e.g., 4, 5, 6, 7, 8, 9 .. . 20±0.1, 0.15, 0.2, 0.25, 0.3, 0.33, 0.375, 0.4, 0.425, 0.45, 0.475,0.5 etc.

Biodegradation

The mechanism of contaminant removal in inventive systems generallyfollows a process involving: surface or internal filtration of suspendedorganics, growth of biomass, absorption of dissolved contaminants by theattached and suspended biofilm, and finally biodegradation. The degreeof biodegradation of the carbonaceous substances in the wastewater canbe determined and quantified by the parameter, 5-day biochemical oxygendemand (BOD₅).

Nitrification

Nitrification and denitrification are typically more complex and morearduous reactions compared to biodegradation of the carbonaceoussubstances, because microorganisms that capture decomposed carbonaceousmaterial build up fast, while nitrifying microorganisms build up slowly.Inventive systems may have the potential for the microbial conversion ofNH₄ (a representation for ammonia and ammonium compounds in the wastewater treatment art) to NO₃ ⁻, which is commonly referred to asnitrification. The limit on denitrification is often the availability ofcarbon for cell synthesis, i.e., approximately 2.5±0.1, 0.1667, 0.2,0.25, 0.33, or 0.5 mg/L BOD₅ per mg/L of NO₃ ⁻ that is converted tonitrogen gas. Denitrification takes place under anaerobic conditions.Therefore, a complete conversion of NO₃ ⁻ to N₂ gas within the knownsystems, and even freshly initiated inventive geotextile and plasticparticle comprising containers would be atypical. However, as thebiofilm layer thickens in the inventive geotextile/particle media, aninner anaerobic layer can form, at which point some denitrification willoccur in the inventive geotextile and plastic particle comprisingcontainers, which may provide complete nitrogen removal, e.g., at least75, 85, 90, 92.5, 95, 97.5, 99, or 99.9 wt. % of the total weight ofnitrogenous compounds.

Design Example

The following example assumes a single house with a wastewater flowrateof 450 gal/day. The wastewater can be first pretreated in the septictank (1) by natural settling. Oil and grease can also be removed (20)from the surface of the septic tank (1), e.g., using a highly adsorptivematerial. The wastewater may then be pumped to the aeration tank (7) ofthe exemplary inventive system for treatment. The septic tank (1) mayhave an effluent filter (21) at its outlet for filtering out the coarseparticles. The wastewater (5) will be pumped (14) to the aeration tank(7), then to the primary decomposition tank (10), comprising thenonwoven geotextile filter (8) and plastic particles (12) for treatment.The following parameters are assumed for the exemplary water treatmentsystem: a flow rate (Q) of 450 gal/day, i.e., ˜1703 L/day; a 5-daybiological oxygen demand (BOD₅) of 150 mg/L; total suspended solids(TSS) value of 40 mg/L; ammonium nitrogen (NH₄—N) of 30 mg/L; ahydraulic loading rate (HLR) of 5 gal/day/ft², i.e., ˜1.758 L/day/m²; adosing cycle of 4 doses/day; a volume for each dose of 112.5 gal/dose(450 gal/day±4 doses/day), i.e., ˜426 L/dose; pump capacity selected(PC) of 100 gal/minute, i.e., ˜378.5 L/minute; a dosing duration of1.125 minutes (112.5 gal/dose±100 gal/minute); total head (TH) for thepump of 12 ft, i.e., 3.66 m; a pump capacity of 10015.5 lb-ft/min, or TH(ft)×PC (gal/min)×density of water (lb/ft³)×1 ft³/7.48 gal×12 ft·×100gal/minute×62.43 lb/ft³×(1/7.48)=10,015.5 lb-ft/min); 1 horse power (HP)is 33,000 lb-ft/min; pump capacity needed is 0.30 HP(10,0155.5÷33,000=0.30 HP); the cross sectional area of the cylindricalexemplary inventive system is 90 ft² (A=Q÷HLR=450 gal/day÷5gal/day/ft²=90 ft²; A is πr² or 90=(π×D²)/4 then the diameter (D) of theprimary decomposition tank (10) is 10.7 ft, i.e., 3.26 m.

A height of the primary decomposition tank (10), i.e., nonwovengeotextile fabrics and plastic particles is 15 ft, i.e., ˜4.57 m. Aheight of the discharge tank is 1.5 ft, i.e., a volume of 135 ft³ with acapacity of holding 1,000 gallons, i.e., ˜3785 L, of wastewater. Aheight of the aeration tank is 1.5 ft, i.e., a volume of 135 ft³ with acapacity of holding 1,000 gallons, i.e., ˜3785 L, of wastewater. Thus,the total height of the exemplary inventive water treatment system is 18ft, i.e., ˜5.49 m, for a volume of 1,620 ft³, i.e., ˜45,873 L or ˜45.9m³, in cylindrical shape of 10.7 ft diameter, i.e., 3.26 m.

Example Results

The removal rate for organic compounds under 5-day biochemical oxygendemand (BOD₅) is shown to be 97% in the above exemplary system. Theremoval rate for total suspended solids (TSS) is shown to be 95% in theabove exemplary system. The removal rate for nitrogenous compounds(NH₄—N) is shown to be 90% in the above exemplary system. Therefore thefinal effluent concentrations from the exemplary inventive systemmodeled will be: 4.5 mg/L final BOD₅; 2.0 mg/L final TSS; 3.0 mg/L finalNH₄—N.

These concentrations are well below the discharge standards (e.g., U.S.National Pollutant Discharge Elimination System (NPDES), allowablewastewater discharge standards to surface water and groundwater for BOD₅and NH₄ are 30 and 10 mg/L, respectively) for surface and groundwater.

While methods of the art, such as Nakao (discussed in the background),can treat wastewater with COD concentrations of 9 to 13.2 mg/L with ca.50% removal efficiency, inventive systems can treat wastewaters with CODof around 200 mg/L, i.e., roughly 20-fold, which is equal to about 150mg/L of BOD₅, with over 95% removal efficiency.

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views.

FIG. 1A shows a two-dimensional pictorial representation of an attachedbiofilm mass within a fiber network represented linearly for simplicity.Generally, the fibers of the nonwoven geotextile will have a non-linearand/or irregular orientation. FIG. 1B shows a two-dimensional pictorialrepresentation floc (suspended, unattached) biomass within a fibernetwork represented linearly for simplicity.

FIG. 2 shows an exemplary arrangement upon which several aspects of theinvention are explained, as described below.

Useful Aeration Tanks

The influent wastewater (5) from a septic tank (1) or pre-treatmentdevice/body should be aerated (6, 13), e.g., in an aeration tank (7)which may be located under the inventive system before introduction intothe primary decomposition tank (10)—inventive geotextile (8) and plasticparticle (12) comprising containers, as depicted in FIG. 2 . Aerationmay be accomplished by an air blower (13), then the effluent (11) can bepumped (14) to the top of the primary decomposition tank (10), i.e.,inventive geotextile and plastic particle comprising container, forfiltration.

Dissolved oxygen concentration can be monitored to make sure that the DOlevels remain at or above, e.g., at least 3 to 4 mg/L or any desiredlevel, including the ranges described above. The dimensions of the(e.g., cylindrical) aeration tank (7) may be generally adapted to thesize of the building or development for which the inventive systems areimplemented, though, for example, a diameter of a useful aeration tank(7) for a 3-bedroom single-family house may be, e.g., at least 9, 9.5,9.75, 10, 10.25, 10.5, 10.75, 11, 11.5, 12, or 12.5 ft and/or up to 15,14, 13, 12.5, 12, 11.5, 11, 10.5, or 10 ft. A height of a usefulaeration tank (7) for a 3-bedroom single-family house may be, e.g., atleast 8, 12, 14, 15, 16, 18, 20, 22, or 24 inches and/or up to 3, 2.75,2.5, 2.25, 2, 1.75, 1.5, 1.25, or 1 ft. For an exemplary aeration tank(7) of 10.7 ft diameter and 1.5 ft height, which may be used within thescope of the invention, a volume of 135 ft³ or 1,000 gallons may be had.

For an exemplary 3-bedroom house, as discussed above total volume ofwastewater requiring treatment is estimated to be roughly 450gallons/day, which may be pumped into an inventive system in, e.g., 4equal doses of 112.5 gal/dose. Of course, a variety of dosing approachesare possible, e.g., 2, 3, 4, 5, 6, . . . 10, etc., as are continuousflow arrangements. In the present exemplary process, the first dose of112.5 gal can be pumped to the aeration tank (7), and the air blower(13) will start running.

Aeration time is important for the conversion of NH₄—N to NO₃ ⁻, whichrequires longer time. A DO analyzer may be installed in the aerationtank (7) to monitor the DO levels. After aerating (13) the wastewater inthe aeration tank (7) for, e.g., at least 1, 1.25, 1.5, 1.75, 2, 2.25,2.5, 2.75, or 3 hours or generally until the DO level reaches at least 3mg/L, then the aeration can be stopped. Post-aeration, the wastewatercan be pumped (14) to the top of the inventive geotextile and plasticparticle comprising container, i.e., primary decomposition container(10), for filtration. In arrangements wherein the aeration tank (7) isabove the primary decomposition tank/container (10), pumps may beavoided. From the base or “post-decomposition” end of the primarydecomposition tank/container (10), the effluent may be recycled to thetop (i.e., beginning point) of the primary decomposition tank (10),optionally through the aeration tank (7). This recycle may continueuntil, e.g., 8 cycles are completed, then the treated wastewater can bedischarged to a nearby receiving water course (22). After completion ofthe processing of a first dose in a batch process having several doses,a second dose, e.g., 112.5 gal of wastewater following the 3-bedroomexample, if accumulated in the septic tank or pre-treatment device (1),can be pumped to the aeration tank (7) and the process will continue thesame as or substantially similarly to that of the first dose. In theexample, this process will continue 4 times until 450 gal of wastewateris treated in the inventive system.

Useful Discharge Tanks

An air/water permeable support plate (16) may be placed right above thedischarge tank (9) in the primary decomposition container (10). Thissupport plate (16) can hold the plastic particles (12) in place and letair and water through to a discharge tank (9). A discharge tank (9) maybe located right above the aeration tank (7) as seen in FIG. 2 . Thedischarge tank (9) may be connected to an aeration tank (9) with a pipe(6), which is controlled with a control valve (19) fordischarge/recirculation placed on the outside face of the primarydecomposition tank (10). This valve (19) will generally be in the “open”position during the recirculation (18) of the wastewater. The valve (19)can turned off (or to an alternate position), and the treated wastewaterwill be discharged (4) from the system to a surface water-body (22) orother water outlet, generally nearby.

Wastewater Recirculation

Incoming wastewater (3, via a wastewater distribution system) from theaeration tank (7) should flow through the primary decomposition tank(10) at a rate that allows microorganisms sufficient time to consume theincoming organic material, i.e., 5-day biochemical oxygen demand (BOD₅).Therefore, the recirculation number can be used to reach a desired levelof treatment. Dosing cycles, organic loading rate, and pump rest periodscan help ensure adequate oxygen in the primary decomposition tank'sfilter media. The biofilm on geotextile filter media (8) and plasticparticles (12) includes aerobic microorganisms requiring oxygen.Intermittent wastewater dosing can provide time for air to re-enter thepore spaces of the geotextile fabric (8) after wastewater is applied.Recirculation of wastewater can help to ensure that the geotextilefilter media (8) and the plastic particles (12) stay wet. In theexemplary 3-bedroom house example, wastewater recirculation may be, forexample, 8 cycles per each volume of wastewater, but it can be reducedor increased depending on the characteristics of the wastewater.

Backwashing

Backwashing (2) can be used to clean the primary decomposition tank (10)filter media (8) and plastic particles (12) to restore and/or improvethe treatment capacity. Backwashing (2) can be performed on a periodicbasis to prevent excess biomass accumulation and head loss build up. Aneffective backwash (2) has to balance the removal of excess biomasswhile keeping adequate attached biomass for wastewater treatment. Watercollected from the primary decomposition tank (10) effluent maypreferably be used for the backwash (2). Accumulated solid particles cantypically be collected and removed from the top of the primarydecomposition tank (10), for example, with mechanisms like those usefulin the septic or pre-treatment tank (1).

Discharge Pipe

The discharge pipe (4) may be controlled with at least one valve (notnumbered) placed on the outside face of the primary decomposition tank(10). As seen in FIG. 2 , the discharge pipe (4) system can be directedto a nearby receiving surface water body (22). The diameter of thedischarge pipe (4) may be, e.g., at least 4, 5, 6, 7, 8, 9, or 10 cmand/or 30, 25, 20, 18, 16, 14, 12, 10, or 8 cm, depending upon thevolume intended to be treated. Such diameters may also be any of theseabove, translated into American units and/or, e.g., at least 2, 2.5, 3,3.5, 4, 5, 6, 8, 10, or 12″ and/or up to 3, 2.5, 2.25, 2, 1.75, 1.5,1.25, 1, 0.75, or 0.5′. The discharge pipe (4) may be made of, e.g.,concrete, steel, glass-coated steel, PVC, high-impact glass, copper,copper-coated steel, galvanized steel, stainless steel, polypropylene(PP), high-density polyethylene (HDPE), acrylonitrile butadiene styrene(ABS), unplasticized polyvinyl chloride (uPVC), post chlorinatedpolyvinyl chloride (CPVC), polybutylene (PB-1), polyvinylidene fluoride(PVDF), temperature resistant polyethylene (PE-RT), and/or cross-linkedpolyethylene (PEX).

FIG. 3 shows a cross-sectional pictorial representation of a nonwovengeotextile fabric operating within the scope of the invention, includingattached and suspended biomass growth, including a zoomed-in portion onthe bottom right illustrating the attached biomass directly attached toexemplary fibers and illustrating suspended (unattached) biomass withina pore of the nonwoven geotextile fabric.

FIG. 4 shows a cross-sectional pictorial representation of exemplaryplastic particles illustrating attached biomass growth on the surfacesof the particles in the zoomed in portion on the lower right.

FIGS. 5A and 5B show pictorial representations of embodiments ofinventive water treatment devices having additional layers, shown areseven packed particle layers (12, and an initial particle layer at theupstream end) with an aeration tank (7) atop the device (FIG. 7A) orwith an aeration/oxygenation device (7 a) attached to or embedded into awastewater feed/effluent recycle pipe (FIG. 5B). Oxygenation may beachieved by a continuous flow interface and/or section of the piping(including extended coils or reroutes), or by an air compression deviceor oxygen comprising gas tank associated with the purification system,which may be bubbled into the contaminated water and/or recycledeffluent (through 24 e). The oxygenation may generally take placeanywhere in the system such that it does not inoculate or excessivelydestroy biomass (e.g., does not reduce nitrification/denitrification).Aeration tanks (7) may be placed to the side, above, or below theprimary decomposition tank (10). An aeration tank may be placed so as toabsorb solar thermal energy to defray potential thermal heating inputs.Moreover, photovoltaic cells may decorate the housing of the primarydecomposition tank (10) so as to provide electrical energy, e.g., to oneor more pumps for mass transport of water in the system (e.g., fordecomposition, cooling, heating, oxygenating, etc.), to one or moreoxygenation devices, such as air compressors, gas regulators, continuousflow oxygenators, etc. While several of the depictions and descriptionsuggest that the housing is cylindrical in shape, the shape of thehousing/primary decomposition tank (10) may be triangular, rectangular(e.g., square), pentagonal, hexagonal, or octagonal prismic, orelliptical (1.5:1, 2:1, 3:1, 4:1, 5:1, . . . 10:1, etc.), with thegeometric designation generally referring to the cross-sectional planeorthogonal to gravity. The tank may also be spherical, e.g., like thatof a natural gas container, or conical (at least in part), wherein thegeotextiles may be adapted to the cross-section of the tank. Thegeotextile layers need not contain additional support structures, e.g.,metal grids or the like, to maintain the general position of theindividual layers, though some applications may employ support elements.Generally, the packed particle layers can be sufficient to support thegeotextile layers. In addition, while the drawings show an initial layerof polymer particles, the initial layer may also be a geotextile layer,just as the final layer may be a geotextile layer (though, for practicalreasons, will generally be a particle packed layer).

Numerous modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described herein.

REFERENCE SIGNS

-   -   1 septic tank/pre-treatment body    -   2 backwash pipe    -   3 wastewater distribution system    -   4 water discharge pipe    -   5 wastewater feeding pipe    -   6 aeration pipe    -   7 oxygenation/aeration tank or well    -   7 a oxygenation/aeration piping, e.g., continuous flow    -   8 geotextitle filter/fabric    -   9 discharge tank    -   10 primary decomposition container, BioGtex tank    -   11 water flow direction    -   12 (recycled) plastic particles/filling    -   13 air compressor (or compressed air or oxygen tank)    -   14 water pump    -   15 water recirculation/discharge structure    -   16 air/water permeable support plate    -   17 water intake structure    -   18 water discharge pipe for recirculation    -   19 control valve for discharge/recirculation    -   20 oil and grease skimmer    -   21 septic tank effluent filter    -   22 surface water-body    -   23 feed    -   24 a-e valves configured to regulate flow

1: A septic water treatment method for removing a carbonaceous and/ornitrogenous compound from contaminated water, comprising: allowing thecontaminated water to settle; removing oil and grease from the surfaceof the contaminated water with an adsorptive material; and aerating thecontaminated water to form a pre-treated water; passing the pre-treatedwater through a water treatment structure system to obtain an effluenthaving a reduced content of the carbonaceous and/or nitrogenous compoundrelative to the contaminated water; wherein the water treatment systemcomprises: a waste water treatment structure, a discharge tankdownstream and in fluid communication with the waste water treatmentstructure; wherein the waste water treatment structure comprises a firstgeotextile fabric layer; a second geotextile fabric layer; a thirdgeotextile fabric layer; a first filler layer comprising plasticparticles, arranged between the first and second geotextile fabriclayers; and a second filler layer comprising plastic particles, arrangedbetween the second and third geotextile fabric layers, and an aerationtank under the first second and third fabric layers and the first andsecond filler layers, wherein the first, second, and/or third geotextilefabric layer comprises at least 75 wt. %, relative to total fabric layerweight, of a nonwoven fabric comprising at least 75 wt. %, relative tototal nonwoven fabric weight, of polypropylene or polyethyleneterephthalate, wherein the aeration tank, geotextile fabric layers andthe filler layers are vertically stacked within a housing, and whereinthe waste water treatment structure is configured such that contaminatedwater proceeds sequentially through the aeration tank, the firstgeotextile fabric layer, the first filler layer, the second geotextilefabric layer, the second filler layer, and the third geotextile fabriclayer. 2: The method of claim 1, wherein the water treatment systemfurther comprises: a fourth geotextile fabric layer; and a third fillerlayer comprising plastic particles, arranged between the third andfourth geotextile fabric layers. 3-9. (canceled) 10: The method of claim1, wherein the first, second, and/or third geotextile fabric layer ofthe water treatment structure, independently has a thickness in a rangeof from 1 to 10 mm. 11-20. (canceled)